In a manufacturing process of a semiconductor, a manufacturing process of a printed wiring board, or the like, microfabrication is required due to the integration of a circuit. In general, a photomask where a circuit pattern is written is manufactured beforehand and a laser light-exposure technique for transferring the pattern to a substrate is used to perform such microfabrication. However, with a method of using a photomask, it takes cost and time to manufacture a mask. Therefore, in recent years, a mask-less process has drawn attention. There is a laser direct drawing method as a typical mask-less process. By the laser direct drawing method, a photosensitive material is discharged onto a conductive film that is formed by sputtering or the like or the upper surface of the conductive film is coated with the photosensitive material, and laser beam irradiation is performed thereover with the use of a laser beam direct drawing apparatus. At that time, the laser beam irradiation is performed selectively and development is further performed to form a mask in a region where the laser beam irradiation is performed. Next, etching of the conductive film with the use of this mask enables the conductive film to be processed into a desired pattern. Accordingly, a circuit pattern of a TFT (thin film transistor) and IC can be manufactured.
In a case where laser irradiation is performed by one laser beam at the time of performing the treatment by a laser direct drawing method, a region that can be processed at a time is limited to one place. Therefore, in a case where it is desired to rapidly perform laser process of a plurality of irradiation points, it is necessary to divide the laser beam into a plurality of beams. As a technique for dividing a laser beam into a plurality of beams and performing laser irradiation, for example, such a laser processing apparatus that has been proposed to divide a laser beam into a plurality of beam spots and perform irradiation with the use of a diffractive optical element (for example, see Patent Document 1: Japanese Published Patent Application No 2002-228818).